The Book on Adler (subtitle: The Religious Confusion of the Present Age, Illustrated by Magister Adler as a Phenomenon, A Mimical Monograph) is a work by the DanishphilosopherSøren Kierkegaard, written during his second authorship, and was published posthumously in 1872. The work is partly about pastorAdolph Peter Adler who claimed to have received a revelation. After some questionable acts, Adler was subsequently dismissed from his pastor duties. Adler later claimed it was work of genius, and not of revelation.

The rest of the work focuses on the concept of authority and how it relates to Adler's situation. Kierkegaard was against claims of received revelation without due consideration.

Let us recapitulate now and see what Adler has done and bear in mind the words of Paul as a motto: “All that is done is done for upbuilding, whether someone speaks in tongues or he prophesies, he does it for upbuilding.” (1 Corinthians 14) In these words is contained the requirement for composure and the ethical responsibility that no one should chaotically think that it is a person’s, to say nothing of a chosen person’s, task to be like a troll-witch. Without having understood himself, without having in the least thought, so it seems, about all the difficult issues he has raised by his assertum [claim] of a revelation, he has haphazardly rushed in upon the established order with his alarming fact. It is the special individual’s business to be very exactly informed about everything related to his difficulty; he has instead left it up to the established order to explain all these difficulties. — Soren Kierkegaard, The Book on Adler, 2009, pp. 257-258

The American philosopher Stanley Cavell helped to re-introduce the book to modern philosophical readers in his collection Must We Mean What We Say? (1969).[1]

Johannes Hohlenberg, a student of Kierkegaard's writings, said of the work: "The book is extraordinarily revealing, because it shows the working of Kierkegaard's mind better than any of the other books. If we want to get an idea of what qualitative dialectics has to say when turned upon a very definite question, we ought to study the book about Adler".[2]